Abstract MP74: Ambient Temperature and Blood Pressure Are Associated in the Jackson Heart Study

Abstract

Extreme temperature events related to climate change may impact blood pressure (BP). Communities of color, especially African-American populations, are disproportionately affected by temperature extremes due to structural inequities. We assessed the association between ambient outdoor temperature and BP among participants in the Jackson Heart Study (JHS), a cohort of African American adults residing in the tri-county area of Jackson, Mississippi. We hypothesized that higher outdoor ambient temperatures would be associated with lower BP. The exposure was average outdoor ambient temperature in degrees Fahrenheit, obtained from Daymet Daily Surface Weather dataset for North America accurate to 1km of Jackson, MS. The two outcomes were systolic and diastolic blood pressure (SBP and DBP). A total of 5309 participants were included across 3 visits: Visit 1 (2000-2004), Visit 2 (2005- 2008), Visit 3 (2009-2013). We used a linear mixed effects model to determine the relationship between ambient temperature and SBP/DBP at three visits. Cardiovascular disease, diabetes, BP medication and visit number were included as adjustment variables. Age, sex, socioeconomic status (captured by level of education, income, and occupation), physical activity, history of cardiovascular disease, BP medications and perceived stress were conceptualized as effect modifiers. To account for non-temperature related seasonal variation in BP, we added season specific coefficients to SBP and DBP readings. The average temperature at each visit was 63.8°F (range: 24.5, 85.6), 64.3°F (range: 30.5, 87.8), 66.3°F (range: 21.9, 90.0), respectively. The average age at baseline was 55.3 years and 63% of the study population was female. For every 10 degrees higher temperature in Fahrenheit, SBP was 0.87 mm Hg (standard error: 0.097, p<0.001) and 0.83 mm Hg (standard error: 0.104, p<0.001) lower in unadjusted and adjusted models respectively. DBP was 0.49 mm Hg (standard error: 0.054, p<0.001) and 0.46 mm Hg (SE: 0.058, p<0.001) lower for every 10 degrees Fahrenheit higher temperature, in unadjusted and adjusted models, respectively. We did not find any significant interactions between the effect modifiers listed and ambient temperature. In conclusion, there was an association between higher ambient temperature and lower blood pressure, independent of season. This study is crucial in understanding how ambient temperature affects BP among African American adults. Greater temperature extremes could lead to greater fluctuation in BP levels with uncertain short and long-term health effects.